Slot antennas are well known in the art.
One problem with existing slot antennas is the coupling between adjacent slots which interferes with the radiation patterns for which the antenna is designed.
The prior art solutions to overcoming this problem of coupling between adjacent slots result in a longer antenna than necessary (forming offset slots on a vertical axis) or making a wider antenna. The latter design is harder to seal for pressurization because of wings or protuberances from the antenna.
It is believed that all existing co-ax slot antennas use an internal feed system. The use of the internal feed lines prohibits use of internal feeder lines.
Broadly in the antenna of the invention, an external microstrip feed system allows adjacent slots to be closer to each other without coupling. This improves the radiation pattern. This external feed system also frees up the internal area of the cylindrical waveguide to allow cable to run inside allowing multi-bay antennas under one radome which simplifies assembly and mounting.
The invention in a preferred embodiment is a slot antenna having a generally cylindrical waveguide and a feed end. A plurality of slots are formed in the waveguide. A plurality of feed strips are secured to the feed end and are secured to the waveguide in spaced apart relationship from the outer surface of the waveguide. Exciters are in communication with the feed strips and extend over the slots. The slots and exciters are dimensioned and arrayed to produce a designed radiation pattern.